The present invention relates generally to the milling of a mortise or series of mortises, and more particularly, to a hand tool for use in such a milling process for facilitating the proper size and placement of such mortises.
Within the field of carpentry, a need frequently arises to mill, often with the assistance of a chisel or mechanical router, a mortise of a particular size and position into the surface of wood or metal. Mortises are particularly needed in doors and associated door jambs for accommodating the leaves of a butt hinge. Such a mortise permits the hinge leaf to be recessed within the surface of the door or jamb, thereby ensuring proper closure of the door.
The mortise size will generally be determined by the dimensions of the hinge leaf. A 4-inch hinge, for example, is wider and longer generally than a 31/2-inch hinge. Therefore, the dimensions could be marked upon the work surface of the door or jamb, the thickness of the hinge leaf determined, and the resulting mortise obtained by removing the wood material therein by means of a chisel, jig, mechanical router, etc. However, such a "freehand" method of milling a mortise would require a great deal of skill and precision in order to obtain a cavity which will fit the hinge leaf without being too large, and which will allow the exposed surface of the hinge leaf to lie flush with the wood surface of the surrounding door or jamb instead of being overly or underly recessed. Moreover, the respective mortises of the door and jamb would need to be positioned exactly alike so that the door and jamb could be properly joined by means of the hinges. Improper milling or placement of a mortise, therefore, would requirement replacement of the door or jamb.
Hence, carpenters or contractors have resorted to the use of a template positioned against the work surface of the door or jamb in order to guide and facilitate the milling of a butt hinge mortise. Moreover, three or more such templates are generally part of a single hand tool so that the spacing between milled mortises may be predetermined and duplicated on both the door and jamb. One such prior art template device is manufactured and sold by Templaco. In consists simply of a long board in which three holes are located. The template is placed against the edge of a door or jamb, and three mortises are routed within the boundaries of the template holes. While simple in design, though, this template suffers from a number of disadvantages. First, there is no versatility between hinge sizes, thereby requiring use of completely separate templates. Second, it is not possible to use the template to mill mortises for either the strike plate positioned along the door jamb, or the latch plate positioned along the edge of the door (used for guiding the latch bolt, which is operated by the doorknob). Third, the template cannot be used for custom jobs in which the butt hinges must be positioned other than where the template holes require. This need usually arises where four hinges are used, or a replacement door is being installed in an existing door frame having unconventional hinge placements. Therefore, the Templaco device suffers from a severe lack of versatility, requiring ownership of multiple templates to accommodate different sizes of hinges, different spacing between hinges, and latch plates, strike plates, etc.
A more versatile template device is manufactured by Bosch, as Model Numbers 83037 or 83002. It consists of three metal template bodies arranged along adjustable extension rails. Each template body, in turn, incorporates metal hinge size plates, usually tightened with thumb screws. They slide toward and away from each other, and are set to match the length of the hinge in question. Adjustable stop pins rest against the edge of the jamb or the face of the door to ensure that the template is properly positioned to produce a mortise of correct width. Therefore, once the Bosch template is assembled for a particular job, adjustments need to be made for hinge length, door length, door thickness, and hinge spacing for each hinge, plus an adjustment for the clearance between the top of the door and the top door jamb. This requires a minimum of thirteen adjustments to the instrument, using difficult to locate knobs and scales, before three mortises may be milled on a door or jamb. Similar devices are manufactured or sold by Skil (Model No. 71022), Black & Decker (Model No. 58129), Porter-Cable (Model No. 59380), and Milwaukee (Model No. 49-54-0100).
Thus, this device is versatile to the point of being far more complicated to operate than is normally required for residential construction, which typically uses 4-inch or 31/2-inch hinges and standard 6'8" doors. Moreover, these devices are expensive, charging most occasional carpenters and home rehabbers for a degree of versatility that will never be used. Furthermore, these devices, like the Templaco template, do not accommodate milling of strike plate or latch plate mortises.
The template of the present invention overcomes these problems associated with the prior art by providing a versatile template for use with a standard 6'8" door, which can accommodate 4-inch and 31/2-inch butt hinges, latch plates, and strike plates; may be used for right or left hand doors; will automatically position the hinges and calibrate the router adjustment needed for variances in thicknesses between 31/2-inch butt hinges, strike plates, and latch plates; does not require assembly or adjustments; is cheaper than most templates commercially available; and is easy to use.